Aspire RAM Upgrade

I need to upgrade the RAM on an Acer Aspire 1640 series laptop. I have tried just lifting up the RAM but it seems to be locked in place. The Service Guide makes no mention of removing the RAm and the User guide only mentions that it 'clicks into place' when you insert the new RAM. Is there a catch I have to release to life up the old RAM, and, if so, where is it, please.

Scroll down to Aspire 1640 user's guide PDF here it shows you need to gently press the ram until it 'clicks' then slide out slightly diagonally towards the hinge side. Reverse of how to install new ram.

Thanks both. I think the various Acer's have slightly different procedures, but I now have at least 3 alternatives to try. Unfortunately, they are now away until early December, and I cannot get to the laptop until they get back. So I've had to put this on hold for the present. However, I will report back as soon as I can.